The Chicago Target Cities demonstration project was designed to improve the effectiveness and accessibility of substance abuse treatment in large metropolitan areas. The primary interventions included centralized intake (CIU), comprehensive standardized assessment procedures, and management of a centralized wait list. A part of this project, the effectiveness of a case management model implemented through the CIU, was tested. Participants were randomly assigned to one of two conditions, case management (CM) or no case management (No-CM). The primary objectives of the CIU case management model were to improve the show rate to treatment, provide referrals to ancillary services, and to support treatment completion. Participants in both groups could also receive other support services provided by staff for the treatment agencies. CM participants were significantly more likely to show to treatment (78.9%) than No-CM participants (71.8%). Case management was found to primarily improve the show rates for younger participants, who without CM were significantly less likely to show for treatment than older participants. CM participants were significantly more likely to receive referrals to non substance abuse treatment services than No-CM participants, although the number of referrals was low in both conditions. No differences were found in the amount or length of substance abuse treatment services received by participants in the two conditions.